A gas turbine engine may include a turbine section with multiple rows or stages of stator vanes and rotor blades that interact or react with a high temperature gas flow to create mechanical power. In a gas turbine engine, the turbine rotor blades drive the compressor and an electric generator to generate electrical power. The compressor can also include multiple rows or stages of stator vanes and rotor blades that compress coolant. The efficiency of the engine can be increased by passing a higher temperature gas flow through the turbine or by increasing the pressure ratio provided by the compressor.
However, the turbine inlet temperature is limited to the vane and blade (airfoils) material properties and the cooling capabilities of these airfoils. The first stage airfoils are exposed to the highest temperature gas flow since these airfoils are located immediately downstream from the combustor. The temperature of the gas flow passing through the turbine progressively decreases as the rotor blade stages extract energy from the gas flow.
Also, the pressure ratio is limited to the airfoil material properties and the cooling capabilities of these airfoils in the compressor. The increase in pressure and proximity to the combustor in later compressor stages causes the temperature within the combustor, and in particular on the airfoil surfaces, to increase.